Circuit Description
This diagnostic test functions on the assumption that a sudden decrease in rear wheel speed must be caused by a brake application. Non-drive wheel speed and stop lamp switch status are supplied to the powertrain control module (PCM) through serial data from the electronic brake and traction control module (EBCM). If there is a 10 km/h (6 mph) or more decrease of non-drive wheel speed in 0.4 seconds and a transition of the torque converter clutch (TCC) contacts at the TCC brake switch or stop lamp switch without a transition of the extended travel contacts of the TCC brake, DTC P1575 is set.
Conditions for Running the DTC
| • | The traction control system and the antilock brake system have not failed. |
| • | The traction control system and the antilock brake system are not active. |
| • | The non-drive wheel speed exceeds 32 km/h (20 mph), and then does not decrease to less than 6.5 km/h (4 mph). |
Conditions for Setting the DTC
A 10 km/h (6 mph) or more decrease in the non-drive wheel speed in 0.4 second, TCC brake switch or Stop/BTSI/Cruise brake switch indicating brakes applied, and no transition is noticed in the extended travel contacts of the TCC brake switch indicating that the brakes applied.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the DTC
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Does the scan tool display indicate Released? | Go to Step 3 | Go to Step 6 |
3 | Depress the brake pedal approximately half-way. Does the scan tool display indicate Applied? | Go to Intermittent Conditions | Go to Step 4 |
4 | Disconnect the extended travel brake switch connector. Does the scan tool display indicate Applied? | Go to Step 10 | Go to Step 5 |
5 | Test for a short to ground on the extended travel brake switch signal circuit. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
6 |
Does the scan tool indicate Released? | Go to Step 7 | Go to Step 8 |
7 | Inspect for poor connections at the TCC and/or extended travel brake switch. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
8 | Test for an open in the ground circuit to the TCC and/or extended travel brake switch assembly. Did you find and correct the condition? | Go to Step 14 | Go to Step 9 |
9 | Test for an open in the signal circuit of the extended travel brake switch . Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
10 | Test for proper TCC and/or extended travel brake switch adjustment. Did the switch require adjustment? | Go to Step 14 | Go to Step 11 |
11 | Replace the TCC and/or the extended travel brake switch. Did you complete the replacement? | Go to Step 14 | -- |
12 | Inspect for faulty connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
13 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 14 | -- |
14 |
Does the DTC run and pass? | Go to Step 15 | Go to Step 2 |
15 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |
